The present invention relates to a surveying instrument, which has a laser pointer.
In a conventional type surveying instrument, when surveying operation is carried out, it has been practiced to perform sighting at first on a measuring point to be measured by using a telescope.
There are several methods to perform sighting using a conventional type surveying instrument. That is, a method to perform visual inspection for sighting on a measuring point by manually operating a telescope while watching into the telescope, a method to acquire an image by a camera built in a telescope and to sight by selecting the measuring point in the image acquired, a method to guide a surveying instrument to the measuring point by using the surveying instrument integrated with a laser pointer and by manually operating the surveying instrument while looking to a projecting point of a laser pointer, a method to control a projecting point of the laser pointer while watching the image and to guide the laser pointer to the measuring point, and other methods.
However, when watching into the telescope or when selecting the measuring point based on an image, since a visual field is limited, it is difficult to direct the telescope in the direction toward the measuring point at a place where a wall surface with few features and the same degree of brightness continuously exists, at a place with a periodic pattern, at a dark place, or the like.
Further, in a case where a laser pointer is directed from a surveying instrument main unit, it is difficult to accurately align the laser pointer with the measuring point if the point is separated by some distance. In a case where the laser pointer is guided by a controller, the movement of the laser pointer does not match the sense of the operator when the measuring point group is tilted, and it is difficult to guide the laser pointer.
Further, in a case where the measuring point is measured directly by a prism, it is necessary to correctly install the prism based on the relation between the measuring point and a constant offset, and this means that much troublesome procedure may be required.
In order to facilitate the guiding to the measuring point, a method is also known. According to this method, the operator moves himself with a prism to a point near the measuring point, using a surveying instrument which has a laser pointer and is capable of tracking the prism and the laser pointer beam projected from the laser pointer is guided to the measuring point. However, when using such type of surveying instrument, a tracking optical axis, a laser pointer optical axis and a distance measuring optical axis all coincide with respect to a visual axis, and the laser pointer beam is reflected by the prism without being projected to a wall surface or the like. As a result, a reflection light of the laser pointer beam cannot be visually inspected, and it is difficult to accurately guide according to the laser pointer.